Lithium-ion doped NiFe_2O_4/SiO_2 nanocomposite aerogel for advanced energy storage devices

摘要

Acid and base mediated sol-gel process followed by supercritical extraction of ethanol used for the synthesis of lithium-ion doped nickel ferrite loaded silica composite aerogels using a high-temperature high-pressure autoclave. The physical-chemical properties of synthesized materials are characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM) and DC-conductivity measurements. The conductivity results suggest that maximum electrical conductivity of 8.63 x 10(-9) Scm(-1) is obtained for 4% Li2O doped 96%{10% NiFe2O4 + 90% SiO2} composite aerogel due to Li+ migration between grain-grain interface and electron hopping between Fe2+ and Fe3+. Further, the XRD result also confirms the formation of amorphous SiO2, Li2O with crystalline NiFe2O4 composite aerogel. FTIR results confirm the bond formation through molecular vibration between Si-O-Si and Ni2+/Fe3+-O. FESEM micrographs reflect the three-dimensional, highly porous interconnected network formation of 4LNS composite aerogel. Aqueous supercapacitor performance of Li2O doped NiFe2O4-SiO2 composite aerogels were examined in 1 molar CH3COONa, Na2SO4 and NaOH electrolytes on respective potential regions of 0.5 to -1 V, 0.4 to -0.8 V and 0 to -1.0 V using three electrode systems. The Li2O addition improves the conductivity and hence improve the specific capacitance of SiO2 and NiFe2O4-SiO2 composite aerogels synergically within the potential window. (c) 2018 Elsevier B.V. All rights reserved.